CHAPTER 2: LITERATURE REVIEW2.1. Service Quality The definition of service quality has been used largely to benchmark teams on customer service excellence. Service quality defined as the overall impression of a service provider, the services and customers often considered equivalent to the overall attitude of the company's customers (Parasuraman et al., 1988). This definition of service quality covers several points. One of them is an attitude to develop in all previous encounters with a service company. Definition of Service Quality: Rust and Oliver (1994) suggested the most recent measurement of the concept of service quality. They offered a three-component model, in which the overall perception of service quality is based on the evaluation of the three dimensions of customer service: 1) Employee engagement (functional or process quality) 2) Service environment and (3) The result (i.e. technical quality). Although the study supports the idea that the environment influences the perception of service quality, it is difficult to make a distinction between the notions of the concept of functional service quality that have been proposed in the literature. For example, researchers suggest three factors, including environment, conditions, service design and social factors. However, the definition proposed by Brady and Cronin (2001) shows that services are part of the service delivery process. In short, for reasons of parsimony, it seems good to include elements of environmental services as part of the components of a functional aspect. (Parasuraman, Zeithaml and Berry, 1985) concluded that service quality can be described on the basis of 10 dimensions. Tangible, reliability… middle of the paper… economically sustainable relationships. He aspired to develop an empirical model of service quality with a particular focus on the banking sector. The objectives of the study are: (1) Identify the critical factors of service quality from the customers' point of view; (2) A tool to measure the quality of service perceived by the customer based on the identified factors with a particular focus on the sector banking;(3) Empirically verify the proposed instrument for uni-dimensionality, reliability and validity using the confirmatory factors approach to analysis. They proposed the 5 critical factors for service quality from customers' perspective, for example, the human element of service provision, essential service or product service, the systematization of service provision, tangible service and social image of the company.